Alex Karpovsky, an actor on HBO’s “Girls,” mainstay of multiple indie comedies and director of some of his own, successfully essays a change-of-pace psychological thriller in “Rubberneck,” enabled by his own perf as a repressed scientist with abandonment issues. Unlike Steven Soderbergh’s twisty “Side Effects,” Karpovsky’s pic seldom surprises, its strengths lying in a leisurely journey toward a clearly predestined denouement. Pic opens Feb. 22 with Karpovsky’s “Red Flag,” and the novelty value of releasing a thriller/comedy double feature, along with the helmer’s TV and indie cred, may spell relatively healthy box office in limited release, given sufficient press.

“Rubberneck” opens on a warmly lit scene of sexual intimacy as Paul (Karpovsky) and fellow lab worker Danielle (Jaime Ray Newman) spend a cozy weekend together. But when Paul attempts to extend the relationship, he is gently but firmly rebuffed, something he visibly struggles to accept. This becomes particularly painful in the sterile environment of the lab, as Paul, working with guinea pigs, alternately strokes them with tenderness and dispassionately dissects them.

Danielle’s affair with married colleague Chris (Dennis Staroselsky) triggers Paul’s full-blown fixation on her, and his efforts to stem the tide — by changing jobs, bonding with his sister (Amanda Good Hennessey) or hanging out with a paid girlfriend (Dakota Shepard) — prove to be in vain.

Karpovsky deploys a panoply of familiar genre gimmicks: the bespectacled Paul half-hidden in lab corridors, spying on the object of his desire, or sneaking around deserted offices gathering intel in order to sabotage the lovers’ relationship. There are even flashbacks to a primal trauma. But these tropes are tempered by an atmosphere resistant to subjective hysteria.

By filming within an actual, functioning scientific lab, Karpovsky at once builds and defuses genre momentum; Paul’s obsession with his beautiful co-worker never completely engulfs the film’s open-ended, character-driven present. The helmer maintains suspense with commendable economy, with nothing milked excessively.

As actor, Karpovsky makes for an odd central figure, too self-conscious and angry to qualify as truly dorky, and too weirdly dissociative for auds to fully identify with. Yet the fallible Paul, never merely frightening, somehow effortlessly commands the screen as an overarching Everyman.

James Lavino’s music adds subtle notes of dread to the mounting tension.